Venus Climate Mission

With this post, I'll complete the longer summaries of the Decadal Survey mission concepts.  Barring breaking news, the next post will provide shorter summaries for several remaining concepts.

While two mission studies plus the SAGE New Frontiers proposal looked at landed missions, the Venus Climate Mission (VCM) would focus on the atmosphere.

The design of the VCM mission is to provide answers to the outstanding science questions about Venus' super-greenhouse gas climate system.  Previous missions have left numerous questions unanswered: "VCM will resolve current uncertainties in atmospheric motions, radiation balance, cloud composition and chemistry, while also making elemental and isotopic measurements that will reveal the origin and evolution of the atmosphere and the evolution of the extreme greenhouse climate."  A key goal will be to understand the relationships and feedbacks between these parameters to enable modeling of Venus' climate and other Earth-like planets.  Another key goal will be to understand how Venus' atmosphere transitioned from what is believed to have been Earth-like to the current extreme CO2 dominated greenhouse.

Winds would be expected to carry the balloon system in a spiral to the pole allowing the study across a range of latitudes.

Previous missions have shown that Venus' atmosphere and weather patterns are highly variable across space and time.  The goal of VCM "will be the first ever truly 3-dimensional (and to a large extent 4-dimensional, including many measurements of temporal changes) characterization of Venus’s atmosphere."  VCM would combine several different platforms to examine the atmosphere from the cloud tops to the surface.  A gondola balloon system would float at 55.5 km altitude for long term studies of atmospheric composition, structure, and winds.  A mini-probe would be dropped from the balloon system at the initial entry to descend to the surface to study composition, atmospheric structure, and winds.  Two small drop sondes would be released from the gondola over the course of its 21 day mission to probe structure and wind from the float altitude to the surface at different latitudes and times of day or night.  A camera on the data relay orbiter would track high altitude cloud movements.

The in-situ VCM elements.  The mini-probe would be released on deployment and the helium tanks would be dropped after balloon inflation.  The drop sondes would be released later to sample different atmospheric conditions from the float altitude to the surface.

Put together, "Simultaneous dynamical measurements from the Gondola/Balloon system and the Mini-Probe and Drop Sondes will allow, for the first time, concurrent measurements of vertical dynamics, cloud particle size and density, and cloud forming species over a wide range of longitudes, solar zenith angles, altitudes and times."

Overall cost of the mission is estimated to fall between approximately $1.1B and $1.6B, which would be slightly more than a New Frontiers mission to a smaller Flagship mission.

Several missions to continue the exploration of Venus' atmosphere from within the atmosphere have been put forward over the last decade.  They range from just a descent probe or a balloon-gondola only platform to multi-element concepts similar to VCM.  The European Venus Explorer (EVE) mission would use international collaboration to deliver a set of platforms that would in many ways be more capable than VCM.  ESA would provide an orbiter with a number instruments to remotely study the atmosphere and surface along with a balloon/gondola that in a summary appears similar to VCM's.  Russia would provide the launch vehicle and a descent probe that would also be a lander.  Japan might provide an additional balloon platform to operate at a different altitude.

Editorial Thoughts: Repeated studies have proposed similar sets of mission elements to answer the key questions about Venus' atmosphere and climate.  The proposals have differed primarily in how many elements were included in response to the possible funding.  Given the climate change occurring on our planet, studying Venus' climate seems a priority to me.  The multi-platforms called for in these proposals would make an international collaboration reasonably straightforward.  NASA, for example, might provide a more capable orbiter, a second descent probe/lander for an EVE, or additional balloons.  Alternatively, Europe could provide a more capable orbiter to compliment VCM's balloon/gondola and descent platforms.   Russia's planned lander would complement either scenario as would NASA's SAGE lander if selected.


The Decadal Survey mission concept studies can be found here.


Other Venus mission proposals with a strong atmospheric focus:


European Venus Explorer
Venus Flagship Lite
Venus Flagship
Venus Balloon

Official Take On NASA Budget Proposal

The following letter from Dr. James Green, NASA's Director of Planetary Science, has written a letter posted yesterday explaining NASA's recently proposed budget and the upcoming release of the Decadal Survey report on March 7.

Dr. Green explains that the decline in the planetary science projected budget in coming years is a result of NASA not being able to include the recommendations of the Decadal Survey in the budget submission.  After the release of the report, NASA will "create a new program structure" that will be reflected in future budget submissions.  He cautions, however, that in the current political climate that, "no one know what Planetary's FY 2012 budget or out year profile [projected future budgets] ... will be once enacted."

Editorial Note: Dr. Green's letter clarifies that the projected budgets for years beyond the current FY12 budget may be increased if necessary to accommodate the Survey's recommendations.  The notes in the budget documents from which I drew my analysis suggested this possibility, but in a political climate promoting flat or declining budgets for federal programs, I did not place sufficient emphasis on this.  I stand corrected, and this position is more encouraging for a vigorous program in the coming decade.

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LETTER FROM DR. JAMES GREEN
Dr. James Green writes about the NASA’s budget and anticipation of the Planetary Science Decadal Survey
Feb. 14, 2011

The President submits his budget to Congress on February 14th. This is a highly constrained budget for NASA taking into account the economic and political times. The Administration has had to make some tough decisions in nearly every area of NASA’s activities resulting in cutbacks or even eliminating some elements. Since we still don’t have a passed FY 2011 budget, the Administration calls the NASA budget from FY 2012-2016 a “notional budget.”

The Planetary Science Division budget just submitted has several important features for everyone to take note. First, although the top line run-out numbers are below the President’s budget projection of last year, the budget in FY 2012 is very healthy and is an adequate budget in a year for which we launch and land the Mars Science Laboratory (MSL), the most challenging scientific and engineering Mars mission ever! Secondly, it is a budget that is in anticipation of the Planetary Science Decadal Survey and; therefore, all potential new strategic missions, regardless of destination are not included in the out years.

Because the Administration is waiting for the results from the Planetary Science Decadal Survey, our out year budget decreases with time through FY 2016. The Planetary Decadal is for the years 2013 to 2022. After the Decadal is released, we will fill in the details, create a new program structure, and step up to the challenges of the next decade’s missions. That said, no one knows what Planetary’s FY 2012 budget or out year profile, just delivered to Congress, will be once enacted. Such is the nature of the times we find ourselves in.

So here is how we must begin to build the next decade’s planetary program. When the survey is released on March 7th (the current projected date), the Division of Planetary Science (DPS) is working with the Decadal Chair, Steve Squyres, to communicate what’s in the Survey, beginning with the planned roll-out at the Lunar and Planetary Science Conference in Houston, through town hall meetings around the country and numerous other ways. My NASA Planetary Sciences team will support this roll-out in every way we can. Why? Over the last two years, we all have invested heavily in support of this Survey. Hundreds of hours have been devoted supporting Dr. Squyres, his committee and subcommittees, with input from over 1600 planetary scientists across the world. I view this Survey as not only reflective of the next decade’s path forward, but also a validation of the foundation we have been building over the past decades. Each mission, each discovery, each success we have made across our planetary portfolio has been another brick in that foundation. Moreover, this Survey will serve as a guidepost to those early career scientists, engineers, and even high school students in making their career decisions and/or trade-offs in their research interests. So, this Survey serves as not just another report in my view, it is a prospectus representing Planetary Sciences’ mutual investment for our future.
I challenge everyone in the community to see themselves and their role in the support of the Survey. My plan is to provide a response before the end of this Fiscal Year. Yes, this is optimistic, but we have a narrow budget process window and also have three launches to focus on. As always, I will continue to solicit your feedback and advice as we begin to implement what is in the Survey.

Bottom line, we must all get behind the new Decadal Survey if we have a chance of having the kind of program that it delineates. If the planetary community becomes divided over the results of the Survey, then I can guarantee that we will have dreams not realized.

Proposed 2012 NASA Planetary Budget

*Because there is no approved FY11 budget, amounts shown are the same as FY10

2010 Planetary Science projected budgets taken from FY11 proposed budget

All other figures taken from FY12 proposed budget

Click on figures for larger versions

Every year, I do a post looking at the President's budget proposal for NASA and its implications for future planetary exploration.  This year, we have two competing budget narratives: the President's and one from the Republican-controlled House in Congress.


Because the President's just released budget proposal has more detail, we'll begin by looking at it.  For FY12, which starts October 1 of this year, the President proposes to increase science spending at NASA by about $500M compared to FY10.  (There is no approved budget for FY11, and agencies are currently funded at FY10 levels.)  The increase is generally split between Earth Science and Planetary Science with other programs approximately flat.  The bump in the Planetary program appears to be largely devoted to supporting the FY12 costs of the Mars Science Laboratory and the Mars MAVEN orbiter development, which hits its peak funding that year.

Beyond FY12, the President proposes to decrease Planetary Science spending, principally by decreasing spending in the Mars and lunar planetary programs.  The Discovery and New Frontiers programs would receive modest increases, and other programs would remain approximately flat.

As I parse the budget, here are implications that come to mind:

• Missions in development would be fully funded: Lunar LADEE, lunar GRAIL, Jovian Juno, Mars Science Laboratory, and Mars MAVEN
• On-going missions such as Cassini and the various missions already at Mars would be funded
• For the third year in a row, the budget proposal includes funding to start up new production of Plutonium 238 to support outer solar system missions.
• The Discovery and New Frontiers projected budgets would support approximately 3 and 2.5 missions respectively (assuming continued funding through 2021 at projected FY16 rates and a fully burdened cost to NASA of ~$800M and ~$1.2B respectively for each mission)

In other NASA budget news, the Republican leadership in the House has proposed holding the NASA FY11 science funding (which is still not approved almost half way into the year) at FY10 levels.  While Congress looks at budgets one year at a time, the Republican leadership has discussed a budget freeze in out years, leading to effective slow budget cuts as inflation takes its bite.  If carried through for the next several years, and if funds for NASA's science programs remain at the same proportion as in FY10, this might mean higher Planetary budgets than the President has proposed.


Editorial Thoughts: Budget politics in the U.S. this year should be either entertaining or nail-biting depending on whether or not you depend of federal budgets for funding. The President's proposal probably represents the upside potential, and the House proposal the downside, and a split near the middle certainly is possible.


For readers who are not American, our budget process is interesting.  The President proposes a budget, and then each house of Congress (the House is currently controlled by the opposition party, the Senate by the President's party) writes its own budget.  Then, through negotiations, the three budget writing parties agree on a compromise that is passed as a law by Congress and signed by the President.  When the process doesn't work, the government generally is funded under a continuing resolution that typically extends the previous year's funding levels.


Budget projections beyond FY12 have far less certainty than even the FY12 proposals.  An interesting experiment is to compare last year's projections with this years, as I did with the dashed line in the first figure.  That dashed line represents the projected spending for the Planetary Program in the Presiden'ts FY11 budget proposal.


Correction: A letter written by James Green, Director of NASA's Planetary Science Program, clarifies that the projected budgets for years beyond the current FY12 budget may be increased if necessary to accommodate the Survey's recommendations.  The notes in the budget documents from which I drew my analysis suggested this possibility, but in a political climate promoting flat or declining budgets for federal programs, I did not place sufficient emphasis on this.  I stand corrected, and this position is more encouraging for a vigorous program in the coming decade.  I've retained the paragraphs that follow which appeared in the original post as an analysis of possible implications if future budgets were to decline as suggested by the out year budget projections.


After accounting for the Discovery, New Frontiers, research, and technology programs, there appears to be around $2.5B plus a bit to support additional missions assuming the projected FY16 budget continues through 2021.  A ~$2.5B wedge would probably support the 2016 and 2018 joint Mars missions with ESA.  It might support a scaled back version of the Jupiter Europa Orbiter.  Without the decline in the Mars program budget (which could be targeted to other missions), the wedge might be another $2B+ larger.


In the press call on the budget, the head of NASA's science program emphasized that the implications of the budget of future planetary missions is well understood.  To paraphrase him, they know that there is not enough funding for a full Discovery program, a full New Frontiers program, a full Mars program, a full outer planets program, etc.  The goal of the Decadal Survey is to decide what should be funded within the budgets expected.  The budget amounts and categories above are not fixed.  In theory, the Survey could recommend ending the Discovery and New Frontiers programs to fund Flagship scale missions for Mars and the outer planets.  (Not an outcome I expect.)


The full budget proposal can be read at http://www.nasa.gov/news/budget/index.html.  The figures in the charts are taken from these documents.

Saturn Probe

The atmospheres around planets contain clues on the conditions in which those planets formed and on how they have evolved.   As a result, missions to place probes into planets have remained a high priority since planetary exploration began.  To date, the atmospheres of Venus, Mars, and Jupiter have been explored in situ by probes.  (In the case of Mars and to a lesser extent Venus, landed missions have conducted composition and structure measurements.)  The Mars Science Laboratory due to land next year will make new and more precise measurements of that world's atmosphere.  If selected in the current New Frontiers competition, the Venus SAGE lander would act as an atmospheric probe during its descent.  The Neptune and Uranus mission concepts include atmospheric probe options to extend measurements to the ice giants.



The Saturn probe mission concept proposes to return to the gas giants with a probe that would complement the Galileo probe's measurements at Jupiter.  In some key respects, the Galileo probe was unable to fulfill its goals because it had the bad luck to descend through a dry atmospheric "desert" that was atypical of the planet.  A mission to deliver a new probe (actually two) to Jupiter was prioritized in the last Decadal Survey.  Unfortunately, the facilities to test probes for the harrowing entry into Jupiter's atmosphere no longer exist.  (A portion of the probe mission's goals now will be performed through remote sensing by the Juno mission.)


Saturn in a way substitutes as a next best option to a new Jupiter probe -- it is the only other gas giant in the solar system.  However, a probe mission to Saturn also would be a compliment.   Saturn is believed to have formed in an adjacent region to Jupiter, and a probe's measurements would help scientists better model conditions in the early solar system.  Measurements could help determine the mechanisms by which the gas giants formed.  In particular, measurements of the abundances of heavier elements would help determine the mechanisms of gas giant formation.


The mission concept prepared by the Decadal Survey is probably the simplest of all the concept missions.  A carrier/relay craft with the probe would arrive at Saturn approximately seven years after launch.  Thirty days or more before arrival, the probe separates from the carrier/relay craft.  The probe would enter the atmosphere and begin measurements at 0.1 bars (a bar is the atmospheric pressure at sea level on Earth).  At 1 bar, the probe would detach from its parachute for a more rapid descent to 5 bars and the end of the nominal mission after 55 minutes of data collection.  The probe would be designed to survive to 10 bars, and the carrier/relay would continue to listen for as long as the entry site remains visible.


The Decadal Survey requested that the study team consider only the simplest mission with a single atmospheric probe and just two instruments: a mass spectrometer and an atmospheric structure instrument.   With just this core mission, the estimated cost would fit into the FY15 New Frontiers mission cost.


The study team notes that an actual mission team might well suggest additional instruments.  From previous studies, additional instruments such as nephelometer to study clouds and haze structure or a net flux radiometer to study energy balance would be among several candidates.  One addition might be a module attached to the probe with a microwave radiometer to conduct deep remote sensing measurements of the atmosphere similar to Juno prior.  (The module would be jettisoned just before entry.)  If funds permit, a second atmospheric probe likely would be a high priority.


Editorial Thoughts: The arguments for atmospheric probes as high priority missions have long been convincing to me.  I hope that the Decadal Survey will propose at least one probe mission.  For me, a Venus probe to better understand the formation of terrestrial worlds and the unique evolution of that world would be highest priority.  (The 1978 Venus Pioneer probes left many unanswered questions that modern instruments could address.)  I would then prioritize a probe to Uranus or Neptune second to explore a different class of worlds.  However, if budgets or the Decadal Survey members better understanding of research priorities results in a Saturn probe, this would be a mission I would whole heartedly support.


There is just one addition that I really would like to see added.  Cameras are now relatively cheap and lightweight.  A camera on the back of the aeroshell and on the probe to take images before and after entry could produce some of the most beautiful images in planetary exploration.  Think of the rings seen from just above or within the atmosphere.  A 2006 Saturn probe summary listed an imager as a possible instrument, so this may not be an impossible wish.
Appendix: Science Objectives


The following objectives, copied from the concept study report, are similar to the goals for most atmospheric probe missions.  With some minor changes, they could be applied to probe missions to Uranus and Neptune.  A Venus probe mission would have goals that echo these but also would be focused on chemical interactions with the surface and evolution of the atmosphere's composition.


Tier 1

• Determine the noble gas abundances and isotopic ratios of H, C, N, and O
• Determine the atmospheric structure at the probe descent location*

Tier 2

• Determine the vertical profile of zonal winds as a function of depth at the probe descent location**
• Determine the location, density, and composition of clouds as a function of depth in the atmosphere**
• Determine the variability of atmospheric structure and presence of clouds in two locations**
• Determine the vertical water abundance profile at the probe descent location**
• Determine precision isotope measurements for light elements such as S, N, and O found in simple atmospheric constituents

*Results would be enhanced with microwave radiometer measures of atmospheric structure prior to probe entry to obtain measurements at depths greater than probe will reach while operating (less useful at Uranus and Neptune because of depth of key structures)
**Measurements from multiple probes would enhance results

The Decadal Survey mission concept studies can be found here.

ESA's Large Mission Selection

The European Space Agency reviewed the status of its three candidates for its large (700M Euro) mission selection slated for this June.  Articles on the journal Nature's website and Space News's website summarize the issues facing ESA in the selection.  Whichever mission is selected is expected to launch around 2022 (which is two years later than I recall, but I haven't been following that date closely).

Three missions are in contention:

Jupiter Ganymede Orbiter (JGO) - Would orbit Ganymede following an intensive campaign of Callisto flybys.  Would compliment a NASA Jupiter Europa Orbiter (JEO) if that mission is prioritized by the Decadal Survey and funded by Congress, but could also fly as a standalone mission.  Apparently no technology readiness issues.  Estimated cost: 710M Euros.

International X-ray Observatory (IXO) - A next generation X-ray astronomy mission that requires contributions from both NASA and the Japanese space agency, JAXA.  The two articles make it clear that the mission depends on novel X-ray optics, but less clear on whether these optics still represent a technology development risk.  ESA estimated cost: 660M Euros.

Laser Interferometer Space Antenna (LISA) - Three spacecraft would fly in formation to become a highly sensitive gravity wave observatory.  The technical challenges behind this mission are substantial, and ESA plans to fly a technology demonstration mission in 2013.  NASA contributions apparently would be required to fly the mission.  ESA estimated cost: 750M Euros.

The ESA costs do not include the funding of instruments that are usually paid for separately by ESA member nations sponsoring individual instruments.

The articles stress that a key challenge for the ESA selection will be lack of commitment from NASA and JAXA for their contributions to IXO and LISA.  The recently completed U.S. astronomy and astrophysics Decadal Survey did not make either mission a top priority, but left open the possibility of a NASA collaboration.  If ESA selects either mission, NASA would have to find funds in its budget to support the mission and Congress would have to approve the funding.  (I don't understand the Japanese budget approval process and don't know how easy or difficult securing its commitment to IXO might be.)

Editorial Thoughts: Perhaps the hardest part about international collaborations for space missions is aligning the decision making and funding processes of multiple space agencies.  From these articles, it appears that ESA would be taking something of a leap of faith to select either IXO or LISA this summer in terms of international partner commitments and technology readiness.  From that perspective, JGO might be the programmatically least risky choice.  Should NASA not proceed with its JEO, then ESA would have the exploration of the Jovian icy ocean worlds to itself for the coming two decades.  (I suspect that if JGO is selected and JEO is not flown, that JGO's mission goals would be expanded to include flybys of Europa.  I've been told by a JPL mission planner that enhancing a Ganymede orbiter to perform Europa flybys should be relatively straightforward to do.)  ESA will have the benefit of knowing NASA's planetary priorities (expected announcement in March) before making its large mission selection.

However, if ESA selects either IXO or LISA, there likley would be considerable pressure on NASA to find funds to support the mission -- both would be great missions.  NASA is also considering partnering with ESA on other astronomy/astrophysics missions, and a larger program of cooperation might be put on the table.

Issues of international collaboration also may influence NASA's planetary priorities.  NASA and ESA have a cooperative Mars program that currently includes the 2016 Mars Trace Gas Orbiter (MTGO) and the 2018 ExoMars and MAX-C rovers.  It's unclear whether MTGO is a committed mission or is subject to Decadal Survey prioritization, but the 2018 rovers mission clearly will be among the missions that the Decadal Survey will prioritize.  ESA does not have the funding to fly the ExoMars mission on its own -- it depends on a NASA launch and a NASA entry, descent, and landing vehicle.  That puts the Decadal Survey in the position of either funding its contribution (I have not seen an estimate, but it would be hundreds of millions of dollars) or leaving the ExoMars rover -- an excellent mission -- stranded.  The decision of whether to fly the NASA MAX-C rover as the first element of a Mars sample return campaign may be made separately.  The Survey could recommend no 2018 Mars mission and leave ExoMars stranded, flying the 2018 mission with the ExoMars rover only, ExoMars and a NASA geophysical station, ExoMars with NASA's MAX-C rover, or ExoMars with NASA's MAX-C rover and a simple NASA geophysical station.  (Hey, if all this was easy, there would be no need for this blog and I would have to find another advocation.)

Mars program planning aside, the two articles mentioned above make me more hopeful about the chances of JGO being ESA's selection is summer.